J/MNRAS/478/1425ivo://CDS.VizieR/J/MNRAS/478/1425doi:10.26093/cds/vizier.74781425CDSSuveges M.Anderson R.I.2024-08-18T20:19:36Z2021-08-20T14:37:25ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frmagellanic-cloudsvariable-starsDetailed knowledge of the variability of classical Cepheids, in particular their modulations and mode composition, provides crucial insight into stellar structure and pulsation. However, tiny modulations of the dominant radial-mode pulsation were recently found to be very frequent, possibly ubiquitous in Cepheids, which makes secondary modes difficult to detect and analyse, since these modulations can easily mask the potentially weak secondary modes. The aim of this study is to re-investigate the secondary mode content in the sample of OGLE-III and OGLE-IV single-mode classical Cepheids using kernel regression with adaptive kernel width for pre-whitening, instead of using a constant-parameter model. This leads to a more precise removal of the modulated dominant pulsation, and enables a more complete survey of secondary modes with frequencies outside a narrow range around the primary. Our analysis reveals that significant secondary modes occur more frequently among first overtone Cepheids than previously thought. The mode composition appears significantly different in the Large and Small Magellanic Clouds, suggesting a possible dependence on chemical composition. In addition to the formerly identified non-radial mode at P_2_~=0.6...0.65P_1_ (0.62-mode), and a cluster of modes with near-primary frequency, we find two more candidate non-radial modes. One is a numerous group of secondary modes with P_2_~=1.25P_1_, which may represent the fundamental of the 0.62-mode, supposed to be the first harmonic of an l {in} {7, 8, 9} non-radial mode. The other new mode is at P_2_ ~=1.46P_1_, possibly analogous to a similar, rare mode recently discovered among first overtone RR Lyrae stars.2018MNRAS.478.1425Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/478/1425CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AcA/65/297 : OGLE4 LMC and SMC Cepheids (Soszynski+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/478/1425https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/478/1425http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/478/1425https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/478/1425https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/478/1425http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/478/1425GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/478/1425/smc (Significant secondary modes in the SMC)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/478/1425/smc?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/478/1425/smc?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/478/1425/smc?GETtext/xml+votable180.050000true6.3606919-73.85394780.005555555555555556Cone search capability for table J/MNRAS/478/1425/lmc (Significant secondary modes in the LMC)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/478/1425/lmc?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/478/1425/lmc?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/478/1425/lmc?GETtext/xml+votable180.050000true71.5263522-68.77548440.0055555555555555564/2068-2069 5/8263 8268-8269 8280-8281 8284 8323 8326 8329 6/32943 32954 33041 33045-33047 33049-33051 33057 33060-33061 33081 33083-33085 33128-33129 33132 33140 33285 33287 33289 33291 33296 33298-33299 33301 33313-33315 33321 33325 33327-33330 33334 33338 33352 33793 33798 33800 37416 37504 37508 37515 37536 37538 37544 37546https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/478/1425?format=asciidefaultJ/MNRAS/478/1425/smcSignificant secondary modes in the SMCrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIdIdentifier from OGLE catalogue name OGLE SMC-CEP-NNNN in Simbad for smc.dat, OGLE SMC-CEP-NNNN in Simbad for lmc.datmeta.id;meta.mainintPer1a? OGLE-III perioddtime.perioddoublenullablePer1b? OGLE-IV perioddtime.perioddoublenullableRemaOGLE-III remarksmeta.notecharRembOGLE-IV remarksmeta.notecharP2? Secondary period found in this studydtime.perioddoublenullableFAP? False alarm probabilitystat.fit.goodnessdoublenullableSecModeSecondary mode of the starmeta.notecharCandModePossible modes for the secondarymeta.notecharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/MNRAS/478/1425/lmcSignificant secondary modes in the LMCrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIdIdentifier from OGLE catalogue name OGLE SMC-CEP-NNNN in Simbad for smc.dat, OGLE SMC-CEP-NNNN in Simbad for lmc.datmeta.id;meta.mainintPer1a? OGLE-III perioddtime.perioddoublenullablePer1b? OGLE-IV perioddtime.perioddoublenullableRemaOGLE-III remarksmeta.notecharRembOGLE-IV remarksmeta.notecharP2? Secondary period found in this studydtime.perioddoublenullableFAP? False alarm probabilitystat.fit.goodnessdoublenullableSecModeSecondary mode of the starmeta.notecharCandModePossible modes for the secondarymeta.notecharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main